Health Library

Hypothyroidism in Children

What is hypothyroidism?

Hypothyroidism is a condition in which the thyroid gland is underactive and doesn't make enough thyroid hormone. Hypothyroidism is the most common thyroid disorder affecting children. However, children with hypothyroidism display different symptoms from adults. If left untreated, hypothyroidism in the newborn (congenital hypothyroidism) can lead to intellectual disability and profound developmental delays.

What is congenital hypothyroidism?

Congenital hypothyroidism (CH) means that inadequate thyroid hormone production has been present since before birth. CH is one of the most common and preventable causes of intellectual disability. Children born in the U.S. are tested for the disorder during their standard newborn screening. Newborn screening is done by state or regional public health programs to detect certain genetic diseases for which early diagnosis and treatment are available. About one out of every 4,000 newborns is diagnosed with CH each year.

Most children born with CH appear normal at birth, usually because the maternal thyroid hormones have sustained the fetus in the womb. Significant signs that the infant may have hypothyroidism are a level of low T4 (thyroxine, a hormone secreted by the thyroid gland that regulates metabolism) and or high level of TSH in the blood. Some infants with CH will have low T4 levels, despite normal TSH levels.

What causes hypothyroidism?

The most common cause of acquired hypothyroidism is an autoimmune reaction in which the body's immune system slowly and silently destroys the thyroid gland. Maternal antibodies produced against a mother's thyroid, or treatment of a mother's thyroid disorder, can affect her unborn child's thyroid function.

What are the symptoms of hypothyroidism?

The symptoms of hypothyroidism in children are different than in adults. The following are the late symptoms of the disorder. Each child may experience symptoms differently, and infants may display subtle or no symptoms. Congenital hypothyroidism has been associated with an increased incidence of congenital abnormalities of the cardiovascular, genitourinary, and skeletal systems. The following are late symptoms of congenital hypothyroidism. Since prompt treatment with thyroid replacement has been shown to prevent brain damage, all newborn infants are screened for low thyroid function. .

Late symptoms in newborns (congenital hypothyroidism):

Jaundice (yellowing of the skin, eyes, and mucous membranes)

Hoarse cry

Poor appetite

Umbilical hernia (navel protrudes out)

Constipation

Slow bone growth

Childhood (juvenile hypothyroidism) symptoms:

Slow growth, sometimes resulting in abnormally short limbs

Delayed tooth development

Adolescents (adolescent hypothyroidism) symptoms:

Slow growth

Delayed puberty

Hoarse voice

Slow speech

Droopy eyelids

Puffy and swollen face

Hair loss

Dry skin

Slow pulse

Weight gain

The symptoms of hypothyroidism may resemble other conditions or medical problems. Always consult your child's doctor for a diagnosis.

How is hypothyroidism diagnosed?

Congenital (present at birth) hypothyroidism is usually detected during the routine newborn screening. Blood samples may reveal abnormally low levels of T4 (the main hormone released from the thyroid or abnormally high levels of thyroid-stimulating hormone (TSH), suggesting hypothyroidism. Released into the blood from the pituitary gland in the brain, TSH increases the size, number, and activity of thyroid cells. TSH also stimulates the release of hormones that affect a person's metabolism and that are essential for normal growth and development. Evaluation may include a scan of the thyroid gland to check for abnormalities.

How is hypothyroidism treated?

Specific treatment for hypothyroidism will be determined by your child's doctor in consultation with you. Considerations include your child's current and past health status, age, medication tolerance, projected disease progression, and your beliefs and attitudes about the treatment alternatives.

Left untreated in newborns, hypothyroidism can lead to intellectual disability. Untreated hypothyroidism may also lead to anemia, low body temperature, and heart failure. The goal of treatment is to restore hormone levels to normal.

Treatment may include prescription of thyroid hormones to replace the deficient hormones. Some children will require hormone replacement therapy for the rest of their lives, while others appear to outgrow the disorder, often by the age of three. Regular monitoring of your child's thyroid hormone levels during the course of treatment can help the doctor diagnose the child's condition more accurately.